A Microscopy and Image Core has been a key, central resource throughout the history of this PPG. Since we have become more interested in the interplay between establishment of cell fate and gene expression in the developing lung, we anticipate continued heavy use of this valuable resource. In addition, to providing assistance for histological techniques and analysis, we have added a flow cytometry and cell sorting component to this Core. This takes advantage of the wide availability of tagged monoclonal antibodies, acknowledges the power of this technique, and is now possible because of an institutional high speed flow cytometry facility. Further, we have also developed the necessary expertise to facilitate our use of a newly available laser capture micro-dissection intsrument. This Core is designed to specifically provide: 1) expertise and consultation in the performance of various histological and flow-cytomtery based techniques 2) formal and practical hands-on training for PPG personnel and post-doctoral trainees in relevant techniques such as immuno-staining, in situ hybridization, image analysis, and flow cytometry data mining 3) management of key equipment and a budget for their maintenance 4) common supplies required for these procedures (paraffin, glass slides etc.) 5) an experienced technician to manage core equipment, teach histological procedures, help standardize new methods, and maintain lab protocols on our department computer server and 6) budgetary support for individual investigator use of institutional instruments (high speed cell sorter and confocal microscope). This PPG has a long tradition of successfully employing immunohistochemistry and in situ hybiridization, and in developing new histological techniques for studies of lung development. This success is due to the efficient management of protocols, reagents, equipment, and the fact that there is daily oversight by the Core by its Director. Within the Core, we now have 3 microscopes with computer software based imaging and analytical capabilities for brighfield, phase, darkfield, and fluorescence microscopy. Further, there are 2 institutional confocal instruments that we will use, and we have ready access to a high-speed cell sorter and analytical cytometry device. Overall, we expect this Core to continue to be a key factor ensuring that the scientific goals of the individual projects will be achieved.